Originally Posted by edge
It may or may not be a fact, BUT it is definitely FRICTION
This is absolutely false.
Barrels NEVER wear out. They can be rechambered to no end.
Some call it when the lands move beyond their tune. Lands are a torch cut point. It might even be stretched to suggest they wear. Especially with very inefficient cartridges(like a 30-06) which blasts the lands at their hottest with a bunch of unburned powder chasing the bullet. Overbore cartridges are like an extra shot of oxygen..
Either way, they don't last long.
But what ultimately kills a barrel(even beyond loose expectations) is carbon constriction. This is similar in affect to a loose bore at the muzzle or a bad crown.
When a bore constricts due to carbon(or carbon ring), so must the bullet -right there.
Now you can allow the throat to cool a bit between shots, and greatly extend life.
But that life will not continue through many rechamberings unless you stay on top of carbon. Otherwise it works it's way into the metal surface, where eventually it can no longer be removed(without ruining the barrel).
That's when a barrel is officially dead..
Those BR shooters brushing and JB pasting, love their barrels. They hope their barrels will love them.